Old Silicone...

[Steve]

Any tips for removing old silicone from around a plastic bath?

Thanks

[Spamlet]

Good luck: even on flat tiles it takes ages with a chisel or razor blade. If there is an easy way to get it off plastic, I'd like to know too.

S

[Spamlet]

Good luck: even on flat tiles it takes ages with a chisel or razor blade. If there is an easy way to get it off plastic, I'd like to know too.

S

[The Medway Handyman]

Buy one of these

a pack of spare blades. They snap regularly.

Keep the blade flat to the bath surface, push into the silicone, then go sideways, so it acts like a big flat knife. Now keep the blade flat against the tiles/wall, push down & then sideways. Most of the silicone will peel off.

Use gently as a scraper to remove any missed bits. As long as you keep it flat you can't damage the bath.

Stanley knife with new blade for corners etc, same technique.

Next - microfibre cloth & white spirit to clean residue.

And don't even try to apply new silicone without one of these

won't believe how good they are until you try one.

HTH

[Phil L]

Yes, silcone eater is a solvent that destroys silicone, you may have to read the blurb as I'm not sure what else it eats

[Spamlet]

Hmm: as this data sheet says to use a bead at least as thick as the bead to be removed, yet it only seems to come in small expensive quantities, it might prove pricey. I'd be interested to know what is really in it. As it warns against using it on anodised aluminium, one would suspect some alkali, though it says it is not water based.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Steve" saying something like:

Aerosol brake cleaner has a loosening action on it, but it's not a solvent. I discovered this by accident.

[Me Here]

Google for silicone remover. Small bottles of the stuff, smells like a cross between oranges and vinegar. I got an really expensive whirlpool spa bath off Fleabay that had silicon still attached, plastic bath and front panel. Painted this stuff on and waited around 10 mins and removed every last trace using a plastic car filler scraper. No damage whatsoever.

[Steve Firth]

Peel off as much as possible being careful not to scratch the bath. Then use diesel or central heating oil to dissolve the residue. The hideously expensive "silicone eater" appears to be nothing more than diesel/kerosene ackaged with a gelling agent.

I discovered the power of diesel to dissolve silicone sealant when I made the mistake of trying to secure a spout to a diesel can using the sealant.

[Man at B&Q]

It's worth it. Just make sure you remove *ALL* trace of it before applying fresh silicone (don't ask). Even at the risk of getting water where you normally don't want it, flood the area and remove *ALL* trace of the damn stuff before applying fresh silicone[1]

Also a =A32.99 plastic silicone remover tool from B&Q. I was surprised how effective it was.

MBQ

[1] I said *ALL*, every last little molecule.

[Man at B&Q]

Greater than 60% Naptha

[Spamlet]

Greater than 60% Naptha

napalm then. Interesting the detail the Ozzy data sheets go into compared with uk ones. Now I come to think of it, I do now recall slimy globs of early silicon rubber sealer ending up blocking carbs, however thinly applied, so, indeed, the stuff is not as impervious as one tends to think. OP should have no problem after all. (But will I remember this next time...)

S

[Fredxx]

Naptha is a general name for petroleum spirit. It isn't the active ingredient which does the dissolving, just the carrier.

[Fredxx]

I find that interesting. I made a silicone sealing ring for a carburretor many years ago, and it outlasted the car. The silicone would have been basic bath sealant. Perhaps diesel has some additives which do rot silicone rubber.

[Jim K]

IME silicone eater doesn't *eat" or *dissolve* silicone it just loosens its adhesion to surfaces and enables you to get any last little bits off after hacking and cutting the bulk out as discussed earlier.

"Components CAS Number Proportion Naphtha (petroleum), heavy alkylate 64741-65-7 >60% C10-14 alkylbenzene sulfonic acid 85117-49-3 10-

[Steve Firth]

What I like about comments like yours is that it shows a particular world-view in which ignoring the preceding evidence in order to parrot a pet theory is seen as the way forward.

[Spamlet]

Apols folks but he is right: both 'naptha' and 'petroleum spirit', are, like 'white spirit', general terms, for particular distillation ranges of the mixture of paraffins and other hydrocarbons one gets from 'cracking' 'crude oils' - and, in the case of white spirit, recycled solvents. (White spirit can be almost anything: I used to test deliveries of it, and some drums could be loaded with water and rusty at the bottom. That's why sometimes it will work in your blowlamp, and other times you can hardly warm your hands on the flame.)

When you specify naptha or petroleum spirit for the lab you just buy by the lowest and highest boiling point you would get if you distilled that particular mixture. This is when you are only interested in the general properties of paraffins, as general purpose solvents and cleaning/burning properties. If you wanted a particular paraffin for a special purpose (rapid or slow evaporation for eg - don't try mouth filling a pipette with n-pentane folks!) , you can buy pure pentane, hexane, heptane, octane etc - but at a much higher price.

The numbers after the name refer to a more detailed specification and Shell describes this mixture as:

"A complex stream of predominately C9 to C12 hydrocarbons; exact composition will vary."

in this case, there will be many unbranched and branched isomers present in a mixture with the general properties that the maker of the silicone 'eater' desired.

Amusingly, another name for these mixes is 'pet ether', so you were actually dead right: this is pet theory.

I would imagine that the surfactant properties of the other benzene sulphonic acid ingredient are what releases the silicone rubber from the substrate, as this is a key ingredient of industrial detergents:

[Spamlet]

As I noted above, this was actually the mistake I made with motorcycle carbs, and got blocked jets as a result. Mind you, I would have been assembling it as a thin smear, wet. If you actually made a gasket and cured it before assembling, you might get away with it. Also, the jets on car carbs might be big enough to suck the goop right through.

Also worth noting is that diesel would be more the composition of the solvent mix used in the remover compound than would the lighter fraction we call petrol or gasolene. Looks like Steve may have missed out on a moneyspinner...

Turned out to be another interesting post indeed.

S

[Fredxx]

The seal was in place of an O-ring. It didn't need to adhere to anything. I would have left it to cure for a long time. It it came away then the old symptoms would have returned, so I'm pretty sure it stayed intact.

[Spamlet]

Put like that, it sounds like a good idea. And now you come to mention it, the 'o' ring seals in our 25 litre drums of iso propyl alcohol looked exactly as if they were indeed made by just a circle of blue RTV bead: and I will now think of making o rings like that in future.

Funny how things all fall into place: serendipity.

Nice one.

S